1. Field of the Invention
The present invention relates to a vehicle wheel with reduction in noise due to air column resonation (cavity resonation) in a tire air chamber.
2. Description of the Related Art
Generally, the air column resonance generated in an air chamber of a tire (hereinafter referred to as tire air chamber) may generate road noise of a vehicle. The air column resonance is a phenomenon that random vibrations of a tire caused by roughness of a road surface cause vibrations of the air in the tire air chamber, and a resonance occurs around an air chamber resonance frequency of a tire air chamber, which generates resonance noise.
JP 3992566 (JP 2004-90669 A) discloses a vehicle wheel capable of reducing resonance noise caused by the air column resonation. The vehicle wheel has a plurality of additional air chambers in a circumferential direction of the rim. More specifically, a lid covers an annular space formed between an annular vertical wall vertically extending from a well portion and extending in the circumferential direction of the rim and a side wall of the well portion extending to a bead seat. A plurality of additional air chambers are formed by sectioning the annular space, defined by the lid, the well portion, and vertical wall, with partition walls equi-distantly disposed in the circumferences of the rim. The tire air chamber is communicated with each additional air chamber through communication holes formed in the lid. This vehicle wheel is capable of reducing the air column resonance in the tire air chamber by forming a Helmholtz resonator with the communication through holes and the additional air chambers.
It is known that water may enter a tire air chamber of a tire due to air charge and deterioration with age. While a vehicle travels, water in the tire air chamber is vaporized. After stop of the vehicle, water is condensed as dew in additional air chambers. Repeat of the cycle causes accumulation of water in the additional air chamber members, which results in variation in a volume of the additional air chamber. This shifts a resonance frequency of a Helmholtz resonator, so that reduction in the air column resonation may decrease. In this case, it is necessary to remove the water in the additional air chambers.
The present invention provides a vehicle wheel capable of keeping reduction effect on noise sound generation for a long time period without maintenance.